Sperm Swim up – Percoll

If you are having difficulties becoming pregnant, you may have decided to try certain fertility treatments in order to increase your chances of conceiving.

Intrauterine insemination (IUI) is often the first type of fertility treatment attempted by couples. In order to get sperm ready for the IUI procedure, it must first be “washed”.

Sperm washing may sound strange, but it actually works to ensure that only the healthiest sperm are used during the procedure. Sperm washing can increase your chances of conception and may help you to welcome a new addition to your family.

Sperm washing is a procedure used to prepare sperm for use in IUI It allows your partner’s sperm a better chance for survival and fertilization. Sperm washing separates sperm cells from a man’s semen, helping to get rid of dead or slow-moving sperm as well as additional chemicals that may impair fertilization. Once sperm has been washed in the laboratory, it can be used during IUI to help achieve pregnancy. There are a variety of different sperm washing procedures.

Simple Sperm Wash

The simple sperm wash technique is the most basic way of washing and preparing sperm for IUI. Semen is diluted in a test tube, with a special solution of antibiotics and protein supplements. It is then placed in a centrifuge, a machine that spins around at extremely high speeds.

As the sperm mixture is spun, sperm cells fall to the bottom of the test tube, producing a mass of dense, highly active sperm. These sperm can then be removed from the test tube and used in IUI. A simple sperm wash takes about 20 to 40 minutes.

Sperm Swim-Up

Semen is placed in a test tube; in some cases, it is previously washed and centrifuged.
A culture medium is carefully placed on top of the semen. The medium is a hospitable environment for the sperm, and healthy sperm will swim up into it. Slow and immotile sperm are left behind, along with most debris in the semen.

The test tube is let stand an hour or so; in some cases it is placed at an angle, and/or in an incubator where past that time the top layer is collected for use.

Finally, the portion retained for use may be washed and centrifuged again.

Density Gradient Sperm Wash (Percoll)

The density gradient sperm wash is one of the most popular sperm washing methods. This is because it also works to separate dead sperm cells, white blood cells, and other waste products from the sperm.

A test tube is filled with multiple layers of liquids of different densities. Semen is then placed on the top layer of liquid and the test tube is spun in a centrifuge. After it is spun, active, healthy sperm will make their way, to the very bottom layer of the liquid in the test tube, while debris and dead sperm will get caught in the top two layers.

These layers can be siphoned off, in order to remove the active sperm from the test tube. This sperm is then used in the IUI procedure. Density gradient sperm washes take approximately 60 minutes.

This procedure is often called just the “Percoll method”, because Percoll was so often used as the density medium, but other density media are now used.

In the early 1980s, researchers reported that it might also cause separation of X and Y-sperm.
This was based on the theory that a) a small fraction of X-sperm are the fastest of all, b) next fastest are the Y-sperm, and c) slowest are the majority of X-sperm.

Later investigation proved that this was not the case, but the method has been promoted in some clinics for gender selection.